Willow species (Salix) are important as short‐rotation biomass crops for bioenergy, which creates a demand for faster genetic improvement and breeding through deployment of molecular marker‐assisted selection (MAS). To find markers associated with important adaptive traits, such as growth and phenology, for use in MAS, we genetically dissected the trait variation of a Salix viminalis (L.) population of 323 accessions. The accessions were sampled throughout northern Europe and were established at two field sites in Pustnäs, Sweden, and at Woburn, UK, offering the opportunity to assess the impact of genotype‐by‐environment interactions (G × E) on trait–marker associations. Field measurements were recorded for growth and phenology traits. The accessions were genotyped using 1536 SNP markers developed from phenology candidate genes and from genes previously observed to be differentially expressed in contrasting environments. Association mapping between 1233 of these SNPs and the measured traits was performed taking into account population structure and threshold selection bias. At a false discovery rate (FDR) of 0.2, 29 SNPs were associated with bud burst, leaf senescence, number of shoots or shoot diameter. The percentage of accession variation () explained by these associations ranged from 0.3% to 4.4%, suggesting that the studied traits are controlled by many loci of limited individual impact. Despite this, a SNP in the EARLY FLOWERING 3 gene was repeatedly associated (FDR < 0.2) with bud burst. The rare homozygous genotype exhibited 0.4–1.0 lower bud burst scores than the other genotype classes on a five‐grade scale. Consequently, this marker could be promising for use in MAS and the gene deserves further study. Otherwise, associations were less consistent across sites, likely due to their small estimates and to considerable G × E interactions indicated by multivariate association analyses and modest trait accession correlations across sites (0.32–0.61).

中文翻译：

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Salix viminalis L.（Salicaceae）中的关联作图-鉴定与生长和物候相关的候选基因。

柳树种（Salix）作为生物能源的短轮转生物量作物很重要，这要求通过部署分子标记辅助选择（MAS）来更快地进行遗传改良和育种。为了找到与重要适应性状（例如生长和物候）相关的标记，以用于MAS，我们通过遗传解剖了柳柳的性状变异（L.）323份材料的种群。这些种质在整个北欧进行了采样，并在瑞典的Pustnäs和英国的沃本的两个田间地点建立，为评估基因-环境相互作用（G×E）对性状-标记关联的影响提供了机会。记录田间测量的生长和物候特征。使用从物候候选基因和先前观察到在对比环境中差异表达的基因开发的1536个SNP标记对这些种质进行基因分型。考虑到种群结构和阈值选择偏差，在这些SNP的1233个与测得的性状之间进行了关联映射。错误发现率（FDR）为0.2时，有29个SNP与芽爆发，叶片衰老，枝条数或枝条直径相关。这些关联的解释范围从0.3％到4.4％，表明所研究的性状受个体影响有限的许多基因座的控制。尽管如此，EARLY FLOWERING 3基因中的SNP仍与芽爆发反复相关（FDR <0.2）。在五级尺度上，罕见的纯合子基因型比其他基因型分类表现出低0.4-1.0的芽爆发分数。因此，该标志物有望用于MAS，并且该基因值得进一步研究。否则，各站点之间的关联就不太一致，这可能是由于它们的估计值较小，以及多变量关联分析和跨站点的适度性状相关性关联所表明的可观的G×E交互作用（0.32-0.61）。